Hi, hoping some one can help me i have a 2003 tdci mondeo which seems to be lacking power. I had a 52 plate before that drove really nice but this one seems very slow. Things i have done all ready, full service cleaned all the boost pipes no splits. There is no smoke at all not one bit cleaned egr valve. There is a thumping noise coming from air box and when i open it up it gets louder. Any help please also there are lights oh dash and had it put on diag machine and no fault codes either i am pulling my hair out

I test drove a 55 plate that done exact same as you've said. I thought the cars must be that slow unti l drove the 1 I have now. Possibly not looked after or driven corectly? Cars made in the last 15 years or so, actually need to be driven quite hard from time to time, allot people drive diesels just about ticking over, which over say 100'000 is no good. Plus being run like that will make it slower than 1 that has been driven harder more often.

When i bought a fiesta st brand new, I asked ford on how to run it in, they said ''you dont, best thing to do is drive it like you stole it if you want it to perform like it should''.

The thumping noise is NOT good though. Are you sure its coming from airbox? have you opened airbox up to see if theres a wee-man in there wi a hammer lol?no seriously though,I'd be worried if I had a thumping noise coming from my airbox.

Are you sure its not engine mount under airbox area? any chance we can hear a video clip of that noise?

you can get a knocking noise with duff injector/s.have you disconnected airbox & had a listen down the air pipe?